Horton

Re: NOT IN subquery optimization

David Rowley <david.rowley@2ndquadrant.com>

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From: David Rowley <david.rowley@2ndquadrant.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: David Steele <david@pgmasters.net>, "Li, Zheng" <zhelli@amazon.com>, "Finnerty, Jim" <jfinnert@amazon.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2019-03-05T23:25:46Z
Lists: pgsql-hackers 
On Wed, 6 Mar 2019 at 03:37, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
> David Steele <david@pgmasters.net> writes:
> > I'm not sure if I have an issue with competing patches on the same
> > thread.  I've seen that before and it can lead to a good outcome.  It
> > case, as you say, also lead to confusion.
>
> It's a bit of a shame that the cfbot will only be testing one of them
> at a time if we leave it like this.  I kind of lean towards the
> two-thread, two-CF-entry approach because of that.  The amount of
> confusion is a constant.

That sounds fine. I'll take mine elsewhere since I didn't start this thread.

-- 
 David Rowley                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services

Commits

  1. Check we don't misoptimize a NOT IN where the subquery returns no rows.